[tex]x=4-\sqrt{5}\ \ \ \ y=\sqrt{5}-4\\\\\\x-y=4-\sqrt{5}-(\sqrt{5}-4)=4-\sqrt{5}-\sqrt{5}+4=8-2\sqrt{5}\\\\Odp.\ B\\\\\\x\cdot y=(4-\sqrt{5})\cdot(\sqrt{5}-4)=4\sqrt{5}-4\cdot4-\sqrt{5}\cdot\sqrt{5}-\sqrt{5}\cdot(-4)=\\\\=4\sqrt{5}-16-5+4\sqrt{5}=8\sqrt{5}-21\\\\Odp.\ D[/tex]
Odpowiedź:
x = 4 - √5 , y = √5 - 4
x - y = 4 - √5 - √5 + 4 = 8 - 2√5
Odp: B
x * y = (4 - √5)(√5 - 4) = - (√5 - 4)(√5 - 4) = - (√5 - 4)² = - (5 - 8√5 + 16) =
= - 5 + 8√5 - 16 = 8√5 - 21
Odp: D
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[tex]x=4-\sqrt{5}\ \ \ \ y=\sqrt{5}-4\\\\\\x-y=4-\sqrt{5}-(\sqrt{5}-4)=4-\sqrt{5}-\sqrt{5}+4=8-2\sqrt{5}\\\\Odp.\ B\\\\\\x\cdot y=(4-\sqrt{5})\cdot(\sqrt{5}-4)=4\sqrt{5}-4\cdot4-\sqrt{5}\cdot\sqrt{5}-\sqrt{5}\cdot(-4)=\\\\=4\sqrt{5}-16-5+4\sqrt{5}=8\sqrt{5}-21\\\\Odp.\ D[/tex]
Odpowiedź:
x = 4 - √5 , y = √5 - 4
x - y = 4 - √5 - √5 + 4 = 8 - 2√5
Odp: B
x * y = (4 - √5)(√5 - 4) = - (√5 - 4)(√5 - 4) = - (√5 - 4)² = - (5 - 8√5 + 16) =
= - 5 + 8√5 - 16 = 8√5 - 21
Odp: D